fix(chat): add ip-based rate limiting to prevent session rotation abuse (#1436)

app/(chat)/api/chat/route.ts

@@ -1,4 +1,5 @@
-import { geolocation } from "@vercel/functions";
+import { checkBotId } from "botid/server";
+import { geolocation, ipAddress } from "@vercel/functions";
 import {
   convertToModelMessages,
   createUIMessageStream,
@@ -31,6 +32,7 @@ import {
 } from "@/lib/db/queries";
 import type { DBMessage } from "@/lib/db/schema";
 import { ChatbotError } from "@/lib/errors";
+import { checkIpRateLimit } from "@/lib/ratelimit";
 import type { ChatMessage } from "@/lib/types";
 import { convertToUIMessages, generateUUID } from "@/lib/utils";
 import { generateTitleFromUserMessage } from "../../actions";
@@ -62,12 +64,18 @@ export async function POST(request: Request) {
     const { id, message, messages, selectedChatModel, selectedVisibilityType } =
       requestBody;
 
-    const session = await auth();
+    const [botResult, session] = await Promise.all([checkBotId(), auth()]);
+
+    if (botResult.isBot) {
+      return new ChatbotError("unauthorized:chat").toResponse();
+    }
 
     if (!session?.user) {
       return new ChatbotError("unauthorized:chat").toResponse();
     }
 
+    await checkIpRateLimit(ipAddress(request));
+
     const userType: UserType = session.user.type;
 
     const messageCount = await getMessageCountByUserId({

instrumentation-client.ts

@@ -0,0 +1,10 @@
+import { initBotId } from "botid/client/core";
+
+initBotId({
+  protect: [
+    {
+      path: "/api/chat",
+      method: "POST",
+    },
+  ],
+});

lib/ai/entitlements.ts

@@ -9,14 +9,14 @@ export const entitlementsByUserType: Record<UserType, Entitlements> = {
    * For users without an account
    */
   guest: {
-    maxMessagesPerDay: 20,
+    maxMessagesPerDay: 10,
   },
 
   /*
    * For users with an account
    */
   regular: {
-    maxMessagesPerDay: 50,
+    maxMessagesPerDay: 10,
   },
 
   /*

lib/ratelimit.ts

@@ -0,0 +1,42 @@
+import { createClient } from "redis";
+
+import { isProductionEnvironment } from "@/lib/constants";
+import { ChatbotError } from "@/lib/errors";
+
+const MAX_MESSAGES_PER_DAY = 10;
+const TTL_SECONDS = 60 * 60 * 24;
+
+let client: ReturnType<typeof createClient> | null = null;
+
+function getClient() {
+  if (!client && process.env.REDIS_URL) {
+    client = createClient({ url: process.env.REDIS_URL });
+    client.on("error", () => {});
+    client.connect().catch(() => {
+      client = null;
+    });
+  }
+  return client;
+}
+
+export async function checkIpRateLimit(ip: string | undefined) {
+  if (!isProductionEnvironment || !ip) return;
+
+  const redis = getClient();
+  if (!redis?.isReady) return;
+
+  try {
+    const key = `ip-rate-limit:${ip}`;
+    const [count] = await redis
+      .multi()
+      .incr(key)
+      .expire(key, TTL_SECONDS, "NX")
+      .exec();
+
+    if (typeof count === "number" && count > MAX_MESSAGES_PER_DAY) {
+      throw new ChatbotError("rate_limit:chat");
+    }
+  } catch (error) {
+    if (error instanceof ChatbotError) throw error;
+  }
+}

next.config.ts

@@ -1,4 +1,5 @@
 import type { NextConfig } from "next";
+import { withBotId } from "botid/next/config";
 
 const basePath = "/demo";
 
@@ -23,4 +24,4 @@ const nextConfig: NextConfig = {
   },
 };
 
-export default nextConfig;
+export default withBotId(nextConfig);

package.json

@@ -49,6 +49,7 @@
     "@xyflow/react": "^12.10.0",
     "ai": "6.0.37",
     "bcrypt-ts": "^5.0.2",
+    "botid": "1.5.6",
     "class-variance-authority": "^0.7.1",
     "classnames": "^2.5.1",
     "clsx": "^2.1.1",

pnpm-lock.yaml

@@ -101,6 +101,9 @@ importers:
       bcrypt-ts:
         specifier: ^5.0.2
         version: 5.0.3
+      botid:
+        specifier: 1.5.6
+        version: 1.5.6(next@16.0.10(@opentelemetry/api@1.9.0)(@playwright/test@1.51.0)(react-dom@19.0.1(react@19.0.1))(react@19.0.1))(react@19.0.1)
       class-variance-authority:
         specifier: ^0.7.1
         version: 0.7.1
@@ -2460,6 +2463,7 @@ packages:
   '@vercel/postgres@0.10.0':
     resolution: {integrity: sha512-fSD23DxGND40IzSkXjcFcxr53t3Tiym59Is0jSYIFpG4/0f0KO9SGtcp1sXiebvPaGe7N/tU05cH4yt2S6/IPg==}
     engines: {node: '>=18.14'}
+    deprecated: '@vercel/postgres is deprecated. If you are setting up a new database, you can choose an alternate storage solution from the Vercel Marketplace. If you had an existing Vercel Postgres database, it should have been migrated to Neon as a native Vercel integration. You can find more details and the guide to migrate to Neon''s SDKs here: https://neon.com/docs/guides/vercel-postgres-transition-guide'
 
   '@xyflow/react@12.10.0':
     resolution: {integrity: sha512-eOtz3whDMWrB4KWVatIBrKuxECHqip6PfA8fTpaS2RUGVpiEAe+nqDKsLqkViVWxDGreq0lWX71Xth/SPAzXiw==}
@@ -2503,6 +2507,17 @@ packages:
     resolution: {integrity: sha512-2FcgD12xPbwCoe5i9/HK0jJ1xA1m+QfC1e6htG9Bl/hNOnLyaFmQSlqLKcfe3QdnoMPKpKEGFCbESBTg+SJNOw==}
     engines: {node: '>=18'}
 
+  botid@1.5.6:
+    resolution: {integrity: sha512-KElecPjc1z6WJ6sCJMw6CvLo/CQclwlLJdobqmtOjVqvCXZZmaWvNafVDwBk0Kf5ordIaorDa3YkIx2OlGx7pg==}
+    peerDependencies:
+      next: '*'
+      react: ^18.0.0 || ^19.0.0
+    peerDependenciesMeta:
+      next:
+        optional: true
+      react:
+        optional: true
+
   buffer-from@1.1.2:
     resolution: {integrity: sha512-E+XQCRwSbaaiChtv6k6Dwgc+bx+Bs6vuKJHHl5kox/BaKbhiXzqQOwK4cO22yElGp2OCmjwVhT3HmxgyPGnJfQ==}
 
@@ -5975,6 +5990,11 @@ snapshots:
 
   bcrypt-ts@5.0.3: {}
 
+  botid@1.5.6(next@16.0.10(@opentelemetry/api@1.9.0)(@playwright/test@1.51.0)(react-dom@19.0.1(react@19.0.1))(react@19.0.1))(react@19.0.1):
+    optionalDependencies:
+      next: 16.0.10(@opentelemetry/api@1.9.0)(@playwright/test@1.51.0)(react-dom@19.0.1(react@19.0.1))(react@19.0.1)
+      react: 19.0.1
+
   buffer-from@1.1.2: {}
 
   bufferutil@4.0.9: